A. Field of the Invention and Prior Art
This invention relates to the construction of cabs or compartments for use on earth moving equipment and other vehicles and more particularly to improved constructions for roll-over protection, for side-tilt cab designs and for sound suppression.
In recent years the design of operator cabs for heavy vehicles such as earth moving equipment has aimed toward operator safety while at the same time avoiding as much as possible the addition of extra weight. It has also been an aim to locate the cab in an optimum position for operator visibility and to maintain a compact arrangement of cab and vehicle while still providing access to the vehicle engine. Some of these objects are realized at least in part by employing a side-tilt cab which is pivotable away from the engine about an axis generally parallel to the longitudinal axis of the vehicle. U.S. Pat. No. 3,578,377 discloses a roll-over protection frame which is mounted on an earth moving vehicle so that the frame may be tilted to one side thereof. Access is thereby provided to the engine compartment within the frame of the vehicle. In this patent, vertical members or posts are secured by pins to brackets which are welded to the vehicle chassis. The roll-over protection frame may be tilted to one side of the chassis by first removing the pins and bolts. A tilt mechanism is further provided which may be actuated to pivotally displace or tilt the roll-over protection frame to one side. While U.S. Pat. No. 3,578,377 discloses the side tilt concept, there is no disclosure of an integrated cab having a supporting post or the like which will collapse allowing the cab to rotate as a unit when the cab contacts the ground during a vehicle roll-over.
Another example of a roll-over protection cab is set forth in U.S. Pat. No. 3,768,856 which discloses restraining links pivotally attached between cab and frame to permit arcuate movement of the cab structure when a certain minimum load is laterally applied thereto. However, these restraining links are not formed as an integral part of the cab structure and thus require additional space on the vehicle.
A pivotally mounted tractor roll bar is disclosed in U.S. Pat. No. 3,527,474 wherein lugs are secured to a roll bar and have apertures through which a sleeve-like rubber insert is disposed, a bolt being inserted to secure the lug to the frame. This patent does not incorporate the roll bar as part of the cab structure, and the rubber flexible inserts are not formed on the struts of the roll-over protection bar.